Effect of high-frequency electric fields on calcium carbonate scaling

The present study conducted an investigation on the effect of high-frequency electric fields (HFEF) in calcium carbonate (CaCO3) scale formation on heated copper tube surfaces. Artificial hard water at varying CaCO3 hardness was used. Calcium carbonate scales were formed on a heated copper tube surface, the fouling thermal resistance was calculated, and the calcium content of the deposited CaCO3 scale was measured by an inductively coupled plasma mass spectroscopy (ICP-MS), and the cooling water was analyzed during the scaling process. No-treatment and HFEF-treatment cases were conducted and compared. The calcium content of the deposited scale dropped by 4-49% in HFEF-treatment case. The lower calcium content of the deposit corresponded to thinner deposits. Water analyses showed consistently lesser percentage drop in HFEF-treatment case primarily due to less fouling deposition. The asymptotic fouling thermal resistance in HFEF-treatment case had a maximum decrease of 88% (i.e., from 4.5 x 10(-4) to 5.4 x 10(-5) m(2)K/W). (C) 2011 Elsevier B.V. All rights reserved.